Linux: Use After Free
CVE-2026-46264 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 6ae479b1919ee9bd0560fc7af649932dd420d010, bf7172cd25ed182f30af2cbb9f80c730dc717d8e as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.11% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 6ae479b1919ee9bd0560fc7af649932dd420d010 or bf7172cd25ed182f30af2cbb9f80c730dc717d8e, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.19.4 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 5c170a4d9c530e872f2f788d95258fbaa39b4415 up to, but not including, 6ae479b1919ee9bd0560fc7af649932dd420d010; 5c170a4d9c530e872f2f788d95258fbaa39b4415 up to, but not including, bf7172cd25ed182f30af2cbb9f80c730dc717d8e; 6.19 | 6ae479b1919ee9bd0560fc7af649932dd420d010, bf7172cd25ed182f30af2cbb9f80c730dc717d8e |
| Linux | Linux Kernel | 6.19 up to, but not including, 6.19.4 | 6.19.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA.
Official description
In the Linux kernel, the following vulnerability has been resolved: drm/xe/pf: Fix sysfs initialization In case of devm_add_action_or_reset() failure the provided cleanup action will be run immediately on the not yet initialized kobject. This may lead to errors like: [ ] kobject: '(null)' (ff110001393608e0): is not initialized, yet kobject_put() is being called. [ ] WARNING: lib/kobject.c:734 at kobject_put+0xd9/0x250, CPU#0: kworker/0:0/9 [ ] RIP: 0010:kobject_put+0xdf/0x250 [ ] Call Trace: [ ] xe_sriov_pf_sysfs_init+0x21/0x100 [xe] [ ] xe_sriov_pf_init_late+0x87/0x2b0 [xe] [ ] xe_sriov_init_late+0x5f/0x2c0 [xe] [ ] xe_device_probe+0x5f2/0xc20 [xe] [ ] xe_pci_probe+0x396/0x610 [xe] [ ] local_pci_probe+0x47/0xb0 [ ] refcount_t: underflow; use-after-free. [ ] WARNING: lib/refcount.c:28 at refcount_warn_saturate+0x68/0xb0, CPU#0: kworker/0:0/9 [ ] RIP: 0010:refcount_warn_saturate+0x68/0xb0 [ ] Call Trace: [ ] kobject_put+0x174/0x250 [ ] xe_sriov_pf_sysfs_init+0x21/0x100 [xe] [ ] xe_sriov_pf_init_late+0x87/0x2b0 [xe] [ ] xe_sriov_init_late+0x5f/0x2c0 [xe] [ ] xe_device_probe+0x5f2/0xc20 [xe] [ ] xe_pci_probe+0x396/0x610 [xe] [ ] local_pci_probe+0x47/0xb0 Fix that by calling kobject_init() and kobject_add() separately and register cleanup action after the kobject is initialized. Also make this cleanup registration a part of the create helper to fix another mistake, as in the loop we were wrongly passing parent kobject while registering cleanup action, and this resulted in some undetected leaks. (cherry picked from commit 98b16727f07e26a5d4de84d88805ce7ffcfdd324)
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 8.4 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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